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authorRussell King <rmk+kernel@arm.linux.org.uk>2013-12-06 12:30:42 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-12-09 23:24:26 +0000
commit9f28cde0bc643186d32744ce69d12222e8588fe7 (patch)
tree708995a3df4183d75957b486c3994004e016459a /arch/arm/mm
parent11d4bb1bd067f9d01d18f620ccfad516dc579593 (diff)
downloadlinux-9f28cde0bc643186d32744ce69d12222e8588fe7.tar.gz
ARM: another fix for the DMA mapping checks
Peter reports that OMAP audio broke with the recent fix for these checks, caused by OMAP audio using a 64-bit DMA mask. We should allow 64-bit DMA masks even with 32-bit dma_addr_t if we can be sure the amount of RAM we have won't allow the 32-bit dma_addr_t to overflow. Unfortunately, the checks to detect overflow were not correct. Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/dma-mapping.c91
1 files changed, 40 insertions, 51 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f6b6bfa88ec..f61a5707823 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -158,13 +158,49 @@ struct dma_map_ops arm_coherent_dma_ops = {
};
EXPORT_SYMBOL(arm_coherent_dma_ops);
+static int __dma_supported(struct device *dev, u64 mask, bool warn)
+{
+ unsigned long max_dma_pfn;
+
+ /*
+ * If the mask allows for more memory than we can address,
+ * and we actually have that much memory, then we must
+ * indicate that DMA to this device is not supported.
+ */
+ if (sizeof(mask) != sizeof(dma_addr_t) &&
+ mask > (dma_addr_t)~0 &&
+ dma_to_pfn(dev, ~0) < max_pfn) {
+ if (warn) {
+ dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
+ mask);
+ dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
+ }
+ return 0;
+ }
+
+ max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
+
+ /*
+ * Translate the device's DMA mask to a PFN limit. This
+ * PFN number includes the page which we can DMA to.
+ */
+ if (dma_to_pfn(dev, mask) < max_dma_pfn) {
+ if (warn)
+ dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
+ mask,
+ dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
+ max_dma_pfn + 1);
+ return 0;
+ }
+
+ return 1;
+}
+
static u64 get_coherent_dma_mask(struct device *dev)
{
u64 mask = (u64)DMA_BIT_MASK(32);
if (dev) {
- unsigned long max_dma_pfn;
-
mask = dev->coherent_dma_mask;
/*
@@ -176,34 +212,8 @@ static u64 get_coherent_dma_mask(struct device *dev)
return 0;
}
- max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
-
- /*
- * If the mask allows for more memory than we can address,
- * and we actually have that much memory, then fail the
- * allocation.
- */
- if (sizeof(mask) != sizeof(dma_addr_t) &&
- mask > (dma_addr_t)~0 &&
- dma_to_pfn(dev, ~0) > max_dma_pfn) {
- dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
- mask);
- dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
- return 0;
- }
-
- /*
- * Now check that the mask, when translated to a PFN,
- * fits within the allowable addresses which we can
- * allocate.
- */
- if (dma_to_pfn(dev, mask) < max_dma_pfn) {
- dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
- mask,
- dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
- arm_dma_pfn_limit + 1);
+ if (!__dma_supported(dev, mask, true))
return 0;
- }
}
return mask;
@@ -1032,28 +1042,7 @@ void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
*/
int dma_supported(struct device *dev, u64 mask)
{
- unsigned long limit;
-
- /*
- * If the mask allows for more memory than we can address,
- * and we actually have that much memory, then we must
- * indicate that DMA to this device is not supported.
- */
- if (sizeof(mask) != sizeof(dma_addr_t) &&
- mask > (dma_addr_t)~0 &&
- dma_to_pfn(dev, ~0) > arm_dma_pfn_limit)
- return 0;
-
- /*
- * Translate the device's DMA mask to a PFN limit. This
- * PFN number includes the page which we can DMA to.
- */
- limit = dma_to_pfn(dev, mask);
-
- if (limit < arm_dma_pfn_limit)
- return 0;
-
- return 1;
+ return __dma_supported(dev, mask, false);
}
EXPORT_SYMBOL(dma_supported);